Breathing mask



FIG. 1 is a top view of the breathing mask.

FIG. 2 is a front view of the breathing mask.

FIG. 3 is a first perspective view of the breathing mask.

FIG. 4 is a side view of the breathing mask.

FIG. 5 is a second perspective view of the breathing mask; and,

FIG. 6 is a rear view of the breathing mask.

The broken line showing of a strap forms no part of the claimed design. 

CLAIM The ornamental design for a breathing mask, as shown and described. 